Washer and settler for gases



Jan. 30, 1951 M. L. COVER 2,539,992

WASHER AND SETTLER FOR GASES Filed March 20, 1948 INVEN TOR.

Mari/)7 L. Col/er BY QMMIWQLIOQW+MJ A T TOPNEYS.

Patented Jan. 30, 1951 UNITED STATES PATENT OFFICE WASHER AND SETTLER FOR GASES Martin L. Cover, Detroit, Mich.

Application March 20, 1948, Serial No. 16,101

. 16 Claims. 1

This invention relates to a washer and settler for gases and has particularly to do with a combined wet washer and settler tank for removing flue dust particles from furnace gases, especially blast furnace gases. v

Blast furnace gases are laden with particles of fuel in the form of coke dust and particles of ore, which if discharged into the atmosphere will constitute a material amount of waste and create a fine deposit of dust in the neighborhood of the blast furnace which is objectionable.

It is common today to use means to remove these suspended particles from the flue gases which are then conducted to coke ovens or to the suitableused for combustible gas. Since the .ore

and coke dust recovered has considerable value and since the reclaimed gas' can be used as combustible gas, the mechanism for making this possible is extremely important. v

Devices commonly in use today consist of a wet washer which is a mechanism for washing the dust from the gas and a Dorr thickener which constitutes a tank which may be 80 feet or more in diameter. Since at least one Dorr thickener tank is usually needed for each blast furnace and since these thickeners are usually partly underground installations, the constitute a considerable investment in equipment and space. Furthermore, they contain moving parts which are constantly subject to corrosive fluids and the abrasive particles in the fluids.

The present invention contemplates a dust remover which occupies about /7 of the ground space required for the Dorr thickener and a device which has no moving parts.

It is an object of the invention to provide a invention toprovide It is another object to provide a construction in which the gas is entirely sealed from the atmosphere and in which blast furnace gas is cleaned, cooled and dried for by-product use.

Other objects and features of the invention relating to the details of construction and operation will be evident in the following description and claims. I

' In thedrawings:

-..ieerer e 1 ecti '1 the dust' mover showing the various elements in the con struction.

Figure 2 is an ensmalled plan view.

A modern blast furnace which has a capacity of around one thousand tons of pig iron a day produces approximately 140,000,000 cubic feet of gas every 24 hours. A furnace of this type is blown at the rate of about 75,000 feet of cubic air per minute and the escaping gases are collected in a closed top in which a constant pressure is maintained. This pressure is sufiicient to force the gas through the outlet pipes to the points of dust recovery. The gas leaving a blast furnace contains considerabl moisture as well as fumes, combustible dust, and iron previously described.

In view of the large quantity of gas that must be handled from any blast furnace it is essential that any dust recovery means be adapted to this large volume without undue pressure or danger of clogging. In Figure 1 I have shown two inlet .pipes I0 and I2 which lead from the top of a blast furnace (not shown). The pipes lfi and I2 fit into the base of a rectangular stack l5 which may be designated a precipitation chamber and which is mounted on a circular sludge collection tank 20. The circular tank 20 may be approximately 30 feet in diameter. The lower portion of the tank 20 has a conical base 22 with a sludge outlet 23. Around the top of th sludge tank 20 1s a drain trough 25 which inclines to an outlet overflow pipe 21. This overflow pipe has two bends 28 and 29 to provide a water seal against the gas pressure within the unit. The top of the tank 20 not occupied by the stack I5 is closed by a cover 32.

In the bottom of the stack [5 is a tapered director section 35 dropping down to a pipe 36 which terminates centrally of the collector tank 20 and vertically about at th middle of the tapered portion 22.

The top end of the stack I5 is closed except for two outlet pipes 40 and 42. the lower end of each being perforated and covered by a plurality of layers of screen. Preferably three layers of 20 mesh copper screen are used. Within the main body of the stack l5 and dividing it centrally is a septum 46 which is suspended from th top 48 of the stack and which extends to a point adjacent the lower end of the tapered portion 35. On each side of the septum 4B are spaced, flowdirecting bafiie plates 41, 48 and 49 which xtend across the stack l5 and parallel to the septum 45. Thetop edges of the plates 41, 48 and 49 are staggered vertically and connected to the respectlvefsides of the tank by perforated fioyc a spray of water.

plates 5|, 52 and 53. These plates may be made of bronze approximately /64 of an inch thick and are so perforated that the are the equivalent of about a 50 mesh screen.

It will be noted that the end of the inlet pipes and I2 overhang inlet opening as shown at 56 and that directly at the openings of the pipes in and I2 is positioned a water spray pipe 58. This pipe extends transversely of the stack l5 and sprays water directly into the gases leaving steam. The steam mixes with the gas and flows upwardly through the screens 5|, 52 and 53 each of which is being exposed from the top to The steam rising to the angled plates is condensed by the cool plates to form droplets of water around each dust particle within the gas and this causes precipitation of most of the dust particles before they reach the top :plate 53. plates 5|, 52 and 53 clean and the condensed The sprays 50 keep the perforated water will flow down the plates between the battles to the pipe 36 where it is fed to the lower most portion of the tank 20. The baffles 41, 48

hand 49 extend downwardly below the water level of tank 26 so that no gas passes upwardly between the baffles.

The gas which finally leaves the screens 66 which surround the perforated ends of pipes All and 32; is relatively dust free and is cooled down 'to a temperature of approximately 150 F. The screens around the pipes 40 and 42 dry the gas so that when it leaves the apparatus it is suitable; for use in pre-treating ovens or gas engines and the like.

The dust particles which have reached the conical portion 22 of the tank settle to the bottom of the tank Where they are drained into an accumulator by a centrifugal pump (not 'shown).

Water will accumulate in the tank 20 until it overflows the edges thereof to trough 25. At the top of the tank the water is sub-- 'stantially dust free and it is carried oif'through the overflow pipe 2'? which, as previously described, has the bends 28 and 29- to provide a water seal and a vent pipe 30 to prevent syphoning.

In some cases a dry dust catcher may be interposed between the above described dust removal' apparatus and the top of the blast furnace,

but this is conventional practice today.

At the sides of the stack l5 are readily removable plates H! which permit quick cleaning of the perforated plates 5!, 52 and 53. The device is so arranged that one pipe H3 or [2 may be cut off by a suitable damper or valve 72 to per- -mit cleaning of one side of the apparatus while the other side is operating. Meanwhile a single sludge tank continues its operation without in- 'moval, drying, and cooling and which occupies "much less space than the average gas cleaner "in use today. l

The device has no moving parts, consequently there is nothing of this nature to wear out or to get out of order.

What I claim is:

l. A gas washer for use in blast furnace operation which comprises a precipitation chamber vertically disposed and terminating at the bottom end in an outlet, a collection tank open to and surrounding the lower end of the precipitation chamber and arranged in gas and water tight relation to the precipitation chamber with respect to atmosphere, a water overflow outlet in said collection tank adjacent the top thereof, means forming a gas inlet for hot waste blast furnace gases to said precipitation chamber above said collection tank, spaced perforate flow plates above said gas inlets, extending in inclined position part way across said precipitation chamber, and water sprays positioned at said gas inlet and above each of said perforate plates to expose the hot gases to a fine spray and elfect steam formation at said inlet and subsequent cooling and precipitation at said perforate fiow plates.

2. A gas washer for use .in blast furnace operation which comprises a precipitation chamber vertically disposed and terminating at the bottom end in an outlet, a collection tank open to and surrounding the lower end of the precipitation chamber and arranged in gas and water tight relation to the precipitation chamber with respect to atmosphere, a water overflow outlet in said collection tank adjacent the top thereof, means forming a gas inlet for hot waste blast furnace gases to said precipitation chamber above said collection tank, spaced perforate flow plates above said gas inlets, and water sprays positioned at said gas inlet and above each of said perforate plates to expose the hot gases to a fine spray and effect steam formation at said inlet and subsequent cooling and precipitation at said perforate flow plates, said perforate plates being inclined downwardly and extending part way across said precipitation chamber in at least one direction to direct precipitated moisture and included dust to said collection tank, and means forming free vertical passages from the collection tank to the space above each perforated plate.

3. A gas washer for use in blast furnace operation which comprises a precipitation chamber vertically disposed and terminating at the bottom end in an outlet, a collection tank open to and surrounding the lower end of the precipitation chamber and arranged in gas and water tight relation to the precipitation chamber with respect to atmosphere, a water overflow outlet in said collection tank adjacent the top thereof, means forming a gas inlet to said precipitation chamber above said collection tank, spaced perforate flow plates above said gas .inlets, and water sprays positioned at said gas inlet and above each of said perforate plates to effect steam formation at said inlet and subsequent cooling and precipitation at said perforate flow plates, said perforate plates being inclined downwardly and extending across said precipitation chamber, and vertical bafile plates suspended in parallel relation from the lower edges of the perforate plates and extending downwardly to a point below the water outlet in said collection tank whereby precipitated moisture and included dust is directed to said collection tank.

4. A gas washer for use in blast furnace operation which comprises a precipitation cham 5 .7 her, a vertical septum dividing said chamber into two parts from top to bottom, said precipi tation chamber having an opening at the bottom thereof, a collection tank open to and surrounding the lower end of the precipitation chamber and arranged in gas and water tight relation in the precipitation tank chamber in respect to atmosphere, a water overflow in said collection tank adjacent the top thereof, gas inlets to each side of said precipitation chamber above said collection tank, spaced, inclined, perforate flow plates above said gas inlets, water sprays positioned in said gas inlets and above each of the said perforated plates to effect steam formation at said inlets and subsequent cooling tation chamber having an opening at the bottom thereof, said opening being materially reduced in cross-section from the section of the precipitation tank proper, a collection tank open to and surrounding the lower end of the precipitation chamber and arranged in gas and water tight relation in the precipitation tank chamber in respect to atmosphere, a water overflow in said collection tank adjacent the top thereof, gas inlets to each side of said precipitation chamber above said collection tank, spaced, inclined,.perforate flow plates above said gas inlets, water sprays positioned in said gas inlets and above each of the said perforated plates to effectsteam formation at said inlets and subsequent cooling and precipitation at said perforate flow plates, and means forming spaced vertical baffles extending from said collection tank to a free edge of each of said inclined perforate flow plates.

6. A gas washer for use in blast furnace operation which comprises a precipitation chamber,

a vertical septum dividing said chamber into two parts from top to bottom, said precipitation chamber having an opening at the bottom thereof, a collection tank open to and surrounding the lower end of the precipitation chamber and arranged in gas and water tight relation in the precipitation tank chamber in respect to atmosphere, a water overflow in said collection tank adjacent the top thereof, gas inlets to each side of 'said precipitation chamber above said collection tank, spaced, inclined, perforate flow platesjabove said gas inlets, water sprays positionedin said gas inlets and above each of the said perforated plates to effect steam formation at said inlets and subsequent cooling and precipitation at said perforate flow 'plates, said perforate plates being inclined downwardly and extending across said precipitation chamber to direct precipitated moisture and included dust to said collection tank, and means forming spaced vertical bafiies extending from said collection tank to a free edge of each of said inclined perforate fiow plates.

'7. A gas washer for use in blast furnace operation which comprises a precipitation chamber, a vertical septum dividing said chamber into two parts, said precipitation chamber having an opening at the bottom thereof; a collection tank operiftot and surrounding theglo'wer end of the precipitation chamber and arranged in gas and eifect steam formation at said inlets and subsequent cooling and precipitation at said perforate flow plates, said perforate plates being inclined downwardly and extending across said precipitation chamber, and vertical bailie plates suspended from the lower edges of the perforate plates in parallel relation to each other and to the vertical septum, the baffle plates and the septum extending downwardly to a point below the water outlet in said collection tank whereby precipitation moisture and included dust is directed to said collection tank.

8. A gas washer is described in claim 1 in g which the outlet of the precipitation chamber is relatively near the bottom of the collection tank and well below the water outlet thereof.

9. A gas washer as described in claim 4 in which the outlet of the precipitation chamber is relatively near the bottom of the collection tank and well below the water outlet thereof.

10. A gas washer as described in claim 6 in which the outlet of the precipitation chamber is relatively near the bottom of the collection tank and well below the water outlet thereof.

11. A gas washer for use in blast furnace operation which comprises a precipitation chamber vertically disposed and terminating at the bottom end in an outlet, a collection tank open to and surrounding the lower end of the precipitation chamber and arranged in gas and water tight relation to the precipitation chamber with respect to atmosphere, a water overflow outlet in said collection tank adjacent the top thereof, means forming a gas inlet to said precipitation chamber above said collection tank, spaced perforate flow plates above said gas inlets, and water sprays positioned at said gas inlet and above each of said perforate plates to effect steam formation at said inlet and subsequent cooling and precipitation at said perforate flow plates, and a gas outlet in said precipitation chamber comprising a perforated open end pipe sur rounded by one or more layers of mesh screen.

12. A gas washer for use in blast furnace operation which comprises a precipitation chamber, a vertical septum dividing said chamber into two parts from top to bottom, said precipitation chamber having an opening at the bottom thereof, a collection tank open to and surrounding the lower end of 1 the precipitation chamber and arranged in gas and water tight relation in the precipitation tank chamber in respect to atmosphere, a water overflow in said collection tank adjacent the top thereof, gas inlets to each side of said precipitation chamber above said collection tank, spaced perforate flow plates above said gas inlets, and water sprays positioned in said gas inlets and above each of the said perforated plates to effect steam formation at said inlets and subsequent cooling and precipitation at said perforate flow plates, and means on opposite walls of said precipitation chamber adjacent said perforate plates selectively removable to permit cleaning of said plates without interruption of said gas washer operation.

13. A gas washer comprising a precipitation l-sllembsr a wlle ion ch mbe ow s d eitati o'n chamber, rneans for maintainin ter level insaid collection chamber above th e bottom of the precipitation chamber, one or finesprayof water at said .gas inlets to be con- ..verted into steam by the heat of the entering gases and means in said precipitation chamber above said inlets to condense said steam and included particles whereby the condensate and particles will drop to the collection tank, said 'gneans comprisingspaced, transverse, perforated platesextendingbetween two sides of said pre- Qcipitation chamber and inclined from another s ide of said precipitation chamber downwardly ward the opposite side, said plates stopping s ort 0f saidvopposite side, and means forming vertical passages from said collection chamber to the space above each perforated plate.

.inore gasinlets to said precipitation chamber i aove the vwater level, means for furnishing a 14. A gas washer comprising a precipitation .elgalnber, a collection chamber below said preicipitation chamber, means for maintaining water level in said .colleetion chamber above the bottom .ofthe precipitation chamber, one or more gas water level, means for furnishing ,a fine spray of water at said gas inlets to be converted into steam by the heat of the entering gases, and

means in said precipitation chamber above'said 30 1,821,090

inlets-to condense said steam and included part cle wh re y t e c densa d P i l s wi :25 inlets to said precipitation chamber above the @l p to th col c io said mea s comprising spaced, transverse, perforated platesextending between two sides of said precipitation chamber andinclined from another side of said precipitation chamber downwardly toward the oppositesides, said plates stopping short-of,;,said

opposite side, and means forming free, vertical passages from the collection chamber to the perforated plate from a point above said plate.

MARTIN L. COVER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 805653 Lowe Nov. 28, 1905 1,176,747 Ferguson Mar.,28, 1916 1,493,579 Walter May 13, 1924 Collins Sept. 1, 1931 2,213,381 Lauer Sept. 3, 194;!) 

